Most non-impact printers which use "burn-off imaging," i.e., burning of marks on aluminized paper by means of electrode arrays, use some form of reciprocating carriage. The carriage moves in one direction to print and in the opposite direction during carriage return. To increase printing speed, the carriage speed must be increased which causes increased dynamics problems and power dissipation.
In addition a reciprocating carriage requires complicated electrical and/or electronic systems for controlling speed, sensing margins, braking, and reversing carriage travel. Various mechanical gearing, clutching and electromechanical switching arrangements are also required to provide requisite control linkage between one or more motors and the carriage.
A large portion of the manufacturing cost of a printer is required for the print head carriage and its controls. A substantial simplification of carriage construction and its controls would provide a substantial reduction in the cost of a printer as well as a reduction in the problems associated with machine dynamics and other inherent maintenance problems related to use of complicated control arrangements.
The present invention contemplates a low cost, reliable and quiet stylus carriage arrangement for use in a printer which substantially reduces the cost thereof; and because of its simple construction and minimum of controls, greatly enhances the reliability of the printer as well as substantially reducing maintenance requirements.
The present invention contemplates a printer employing a continuously revolving endless belt having at least two sets of stylii or print heads attached thereto for moving each stylus over the paper. Each stylus comprises a plurality of wires formed at one end into a writing tip which contacts the electrically conductive paper as it is moved across the paper by the belt. The belt itself is made of an insulating material with a plurality of conductive strips disposed on the surface of the belt and extending around the outer periphery thereof. The stylus wires are electrically connected to respectively positioned conductive strips. The belt is disposed about a pair of spools, one of which is motor driven. The other spool may be spring loaded to provide belt tension. Current is supplied to the stylus via the motor-driven spool which is a commutator and a slip ring assembly in tandem with the commutator spool or by a brush assembly in contact with the conductive strips of the belt.